Apparatus and Method for Garbage Collection

1. A garbage data collection method performed during a communication cycle of a plurality of communication cycles of a computing device having memory including writeable non-volatile memory, the garbage data collection method comprising: performing a mark phase during a communication cycle, the mark phase for making a first list, the first list being an address list including addresses of objects to be deleted from the memory; performing a first sweep phase during the communication cycle to delete objects listed in the first list from the memory, wherein the performing of the sweep phase comprises: calculating a residual time up to a predetermined time limit after processing an external command; after calculating the residual time, deleting objects listed in the first list from the memory during the calculated residual time; and updating the first list to include addresses of remaining objects listed in the first list of objects to be deleted which cannot be deleted within the calculated residual time, and storing the updated first list in the memory separately from the objects so as to prevent deletion of the first list.

2. The method of claim 1 , wherein the time limit is determined by a host that transmits the external command or the time limit is determined to be a period of time up to a time guaranteeing QoS that a user does not feel a response delay to the external command.

3. The method of claim 1 , wherein the act of making the first list is performed when a garbage collection is requested or when a communication session for receiving the external command is initialized.

4. The method of claim 1 , wherein the act of making the list of objects comprises: adding to the first list an address of an object that was to be deleted in a prior communication cycle but remains in the memory undeleted.

5. The method of claim 1 , wherein the act of making the list of the objects comprises: updating the first list of when an object is newly generated or deleted during the command processing.

6. The method of claim 1 , wherein the act of deleting the objects of the first list comprises: making a second list including addresses of objects to be deleted from the memory during any residual time remaining after deleting all objects listed in the first list.

7. The method of claim 1 , further comprising: during the communication cycle, deleting objects listed on existing list which remain undeleted after a prior communication cycle before the external command is processed.

8. The method of claim 1 , further comprising: if the command includes a memory write command or an object delete command, and if there is a list including addresses of objects to be deleted from the memory before the write or delete command is processed, performing the deleting of the objects together with the write or delete command.

9. The method of claim 1 , wherein the deleting of listed objects comprises: if the objects listed in the first list exist in the memory in a consecutive order, deleting the consecutively ordered objects all together, and if a memory space to be allocated for an object and a memory space of the objects listed in the first list are consecutively ordered memory spaces or the same memory space, performing the acts of allocating and deleting together.

10. A garbage collection apparatus comprising: a timer, which calculates a residual time up to a predetermined time limit after processing an external command; and a memory management unit, which performs a mark phase during a communication cycle, the mark phase for making a list including addresses of objects to be deleted from a memory, and performs a first sweep phase during the communication cycle for deleting objects listed on the of list from the memory, wherein the sweep phase comprises deleting objects listed on the list from the memory during the calculated residual time, updating the list to include addresses of remaining objects listed in the list of objects which cannot be deleted within the lapse of the calculated residual time, and storing the updated list in memory separately from the objects so as to prevent deletion of the first list.

11. The apparatus of claim 10 , wherein the memory management unit deletes objects listed on an existing list which includes addresses of objects which remain undeleted after a prior communication cycle before the external command is processed.

12. The apparatus of claim 10 , wherein the memory management unit, if the command includes a memory write command or an object delete command, and if there is a list including addresses of objects to be deleted from the memory before the write or delete command is processed, performs the deletion of the objects together with the write or delete command.

13. A computer readable medium having recorded thereon a computer readable program for performing a garbage data collection method performed during a communication cycle of a plurality of communication cycles of a computing device having memory including writeable non-volatile memory, the garbage data collection method comprising: performing a mark phase during a communication cycle, the mark phase for making a first list, the first list being an address list including addresses of objects to be deleted from the memory; performing a first sweep phase during the communication cycle to delete objects listed in the first list from the memory, wherein the performing of the sweep phase comprises: calculating a residual time up to a predetermined time limit after processing an external command; after calculating the residual time, deleting objects listed In the first list from the memory within the calculated residual time; and updating the first list to include addresses of remaining objects listed in the first list which cannot be deleted within the calculated residual time, and storing the updated first list in the memory separately from the objects so as to prevent deletion of the first list.